Added the thread that finds perfect numbers and related functions.

Still need to implement the other thread (listen for a kill signal).
Still need to deal with signals in the perfect numbers thread.
Added many more functions to compute.c (and changed some).

Changed from threads to processes, seems easier for now.
Added a handle_sigs() function, use to create signal handlers (sigaction)

As of right now, the numbers process is the parent process, not sure if it matters. For now
I'm keeping it that way. I don't see any reason to spend time deciding which one should
be the parent. Coding will go faster if I focus on more important things.

Finally, the handle_sigs() function may need some work. I am unsure if the "void (*sa_handler)(int)"
will work for passing a function.
Small amount of changes, closing this branch.

I'll be moving onto manage.py (the server).

Once I have that up, I'll try a basic connection and see what happens.
Merge branch 'feature/compute_socket' into develop